Progressive Keratoconus
Conditions
Keywords
corneal crosslinking
Brief summary
Three different protocols for inducing corneal crosslinks in subjets with progressive keratoconus will be evaluated in this randomised clinical study.
Detailed description
Riboflavin does not penetrate the intact corneal epithelium. Corneal cross linking (CXL) is typically performed using the so-called Dresden protocol. The Dresden protocol states 30 minutes of UVA-radiation (3mW/cm2) but a 10 minute irradiation protocol (9mW/cm2) is frequently used. Both of the protocols involve mechanical removal of the epithelium over the central 8 mm of the corneal surface. The first days after treatment therefore involves some degree of pain, often intense, and the presence of a healing epithelial defect may be associated with development of infiltrates in the cornea. A number of approaches have been evaluated in order to promote riboflavin penetration through the intact epithelium, of which iontophoresis appears most promising. Keratoconic corneas are thin at the cone location and sometimes it is difficult to maintain the safety margin of 400 microns during corneal crosslinking. Instead of using isotonic standard riboflavin, a swelling effect of the cornea can be obtained by using hypotonic riboflavin. However, the latter has been indicated as less effective in the process of inducing cross links. Eighty-one of 81 patients of various degrees of keratoconus will be randomised to one of the following groups: 1) CXL (UVA 9mW/cm2) using isotonic riboflavin, or 2) CXL (UVA 9mW/cm2) using hypotonic riboflavin or 3) Iontophoresis with Ricrolin with following CXL (UVA 9mW/cm2). Hypothesis: i) CXL with hypotonic riboflavin or CXL with Ricrolin administered by iontophoresis or CXL with isotonic riboflavin is non-inferior compared to standard CXL with isotonic riboflavin. ii) The morphological structure post-CXL in the three different groups will be similar without any significant differences. The iontophoresis-assisted treatment arm has been interrupted due to low efficacy in halting disease progression. The results have been published.
Interventions
PROCEDURECorneal crosslinking: CXL (UVA 9mW/cm2)
CXL treatment with UVA-radiation (9mW/cm2) with a 10 minute irradiation protocol.
CXL protocol with isotonic riboflavin
CXL protocol with hypotonic riboflavin
PROCEDUREIontophoresis
CXL protocol with iontophoresis and ricrolin
Sponsors
Region Skane
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Prospective randomized interventional clinical trial
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Progress in keratoconic eye. We define progress as an increase in Kmax of 1.0 diopter in 1 year or 0.5 diopter in 6 months. This increase in Kmax will be accepted as progression if concomitant changes tomographic parameters.
Exclusion criteria
* Concurrent ocular infection or corneal disease other than keratoconus. * Pregnancy. * Treatment with Isotretinoin.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative change in visual acuity | Patients will be evaluated 1, 6, 12 and 24 months after treatment. | Uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity (BSCVA) |
| Postoperative change in Kmax | Patients will be evaluated 1, 6, 12 and 24 months after treatment. | Maximum corneal steepness |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative change in Keratocyte cell density | Confocal microscopy will be performed at 6 and 12 months. | Keratocyte cell density will be evaluated using confocal microscopy |
| Postoperative change in endothelial cell count | Confocal microscopy will be performed at 6 and 12 months. | Endothelial cell count will be evaluated using confocal microscopy |
| Postoperative change in astigmatism | Patients will be evaluated 1, 6, 12 and 24 months after treatment. | Corneal astigmatism |
| Postoperative change in the corneal thickness during CXL treatment | Corneal pachymetry will be evaluated before and then every 5 minutes during 30 minutes under CXL treatment. | Corneal pachymetry is the process of measuring the thickness of the cornea |
| Postoperative change in demarcation lines | Confocal microscopy will be performed at 6 and 12 months. | Identification of the demarcation lines with confocal microscopy will help establishing how deep was the effect of the CXL treatment. |
| postoperative change in corneal nerve cell density | Confocal microscopy will be performed at 6 and 12 months. | Corneal nerve cell density will be evaluated using confocal microscopy |
Countries
Sweden
Outcome results
None listed